Antihypertensive effect of heshiko, a fermented mackerel product, on spontaneously hypertensive rats

ABSTRACT:   During the processing of heshiko , a fermented mackerel product, a rapid increase in peptide content in the extract and a remarkable decrease in the IC₅₀ (the inhibitor concentration to inhibit 50% of enzyme activity) as an index of the angiotensin I-converting enzyme (ACE) inhibitory activity were observed. Systolic blood pressure (SBP) in spontaneously hypertensive rats (SHR) decreased between 2 and 4 h after single oral administration of heshiko extract at a dose of 10 mg/kg as a peptide, and SBP recovered its initial level by 8 h. For single doses of extract at three different levels (5, 10 and 50 mg/kg), SBP similarly decreased after between 2 and 4 h. The decreased SBP at 50 mg/kg was almost equal to that at 10 mg/kg, indicating a low dose dependency for heshiko extract. Through successive administration of heshiko extract or its desalted extract at 10 mg/kg for 10 days, SBP decreased 7 days after the start of administration and it recovered its initial level 5 days after stopping administration. During these periods, the change in ACE activity in blood plasma from SHR administered the extract roughly corresponded to that of SBP, suggesting that ACE inhibition was related to a decrease in SBP. For long-term administration of the extract to 5-week-old SHR for 70 days, SBP decreased 28 days after the start of administration. The decreased SBP remained low for 28 days after stopping administration, whereas the decreased ACE activity recovered its initial level. These results suggest that heshiko extract influences not only ACE inhibition, but also other systems that regulate blood pressure.     

Color effects of lures on the hooking rates of mackerel longline fishing

SUMMARY: This study attempts to understand the color effects of artificial lures on the hooking rate of mackerel longline fisheries in Taiwan waters. From the results obtained from field work, the order of hooking rates from the different colored lures was red > black > yellow-green > yellow-orange = reddish orange = pink > white > blue > purple > transparent. Transparent, purple and blue lures had the smallest hooking rates and showed significant differences (least significant difference test) from the other colored lures. However, no significant differences could be found among the hooking rates of the other colored lures. In addition, the lumiunous reflectance of nine different gray lures did not show any significant difference in the hooking rates. Therefore, it is likely that the 'spectral' (colored) effects are the major influence causing the differences in hooking rates and the luminous effects play only a minor role in artificial lures.     

利用鲅鱼皮、骨制作海鲜味香精的工艺条件研究

本研究利用鲅鱼皮、骨经酶解后进行美拉德反应制备海鲜味香精。根据酶解原料被水解下来的游离氨基酸态氮含量来确定最佳的酶解条件;通过单因素和正交实验,以热反应产物的感官评分优化得出美拉德反应参数。结果显示:在料液比为1∶4、复合蛋白酶(FHY-G-Ⅷ)添加量为1.6%,且温度为50℃、pH 7.0条件下酶解4.5 h,每100 g鲅鱼皮、骨所水解下来的游离氨基酸态氮含量最高为4.8%;将获得的酶解液进行美拉德反应,最适的物质配比及热反应条件为:还原糖添加量(木糖∶葡萄糖=1∶1)为4%、氨基酸(甘氨酸∶谷氨酸=1∶2)3%,在pH 8.0、110℃条件下反应50 min,所得产品为均一的红褐色液体,具有浓郁的酱香味和鱼香味,无鱼腥味,其游离氨基酸态氮含量为0.42%。     

日本鲐鱼油在不同条件下的脂质氧化

粗制与精制日本鲐鱼油贮藏于以钨丝灯泡为光源或避光条件下，分析了光氧化对鲐鱼油精制前后的氧化稳定性以及丁基羟基茴香醚(BHA)和叔丁基对苯二酚(TBHQ)的抗氧化性，并观察其过氧化值(POV)和硫代巴比妥酸(TBA)值在5℃和40℃下18天内的变化。结果表明，可见光是加速鲐鱼油氧化的重要促进因素，抗氧化剂能明显延缓其氧化，其中TBHQ比BHA效果更好，其氧化速率的顺序光照＞光照+BHA＞避光＞光照+TBHQ＞避光+BHA＞避光+TBHQ；精制鲐鱼油的POV和TBA值较粗制鲐鱼油高；高温贮藏的精制鲐鱼油只在光照条件下氧化速度加快。     

Thermal gelation behaviors of surimi protein mixed with Hydroxypropylmethylcellulose

ABSTRACT:   This study examined the thermal gelation characteristics of myofibrillar protein (MP) and salt-ground horse mackerel surimi that had been mixed with hydroxypropylmethylcellulose (HPMC). Analysis, using thermal scanning rigidity monitor and differential scanning calorimetry, demonstrated that thermal gelation begins in the thermo-reversible HPMC gel used in this study at approximately 60°C. In the rescanning test, first scanning diagrams showed similar pattern, but second scanning diagrams were rather diverse between MP and MP/HPMC mixture. The addition of HPMC increased rigidity of salt-ground surimi and modified the thermal gelation during the heating process, suggesting that certain enhancing effect of gelation occurred when the mixture of MP and HPMC was heated. In the annealing test, the addition of HPMC lowered the breaking force, but increased the gel strength of surimi due to a substantial increase in deformation. Although the strong cross-linking between the two components might not occur during the gelling process, HPMC gel formed at high temperature occupies some space in thermal gel by interacting with proteins and resulted in a combinative gel with a higher rigidity and gel strength at higher temperature.     

闽南—台湾浅滩渔场鲐鲹鱼类群聚资源生产量和允许总渔获量

以海洋生态系营养动力学为基础,采用Steele模式估算闽南—台湾浅滩渔场中上层鱼类资源年生产量为86.14×10~4t,进而以鲐鲹鱼类群聚资源在中上层鱼类资源的比例,估算鲐鲹鱼类群聚资源的年生产量为51.76×10~4t。Gulland和MSY简单模式估算鲐鲹鱼类群聚资源的最大持续产量分别为25.00×10~4t和25.88×10~4t。Schaefer和Fox剩余产量模式估算鲐鲹鱼类群聚资源的最大持续产量分别23.60×10~4t和23.41×10~4t,最大持续捕捞力量分别为1140.41×10~4kw·d和1266.66×10~4kw·d。折算为福建灯光围网渔船分别为424和471组,并从开发现状和种群生态学及捕捞死亡等参数分析鲐鲹鱼类群聚资源的开发前景。     

Effect of low salinity on the expression profile of Na+/K+‐ATPase and the growth of juvenile chub mackerel (Scomber japonicus Houttuyn)

Chub mackerel (Scomber japonicus Houttuyn) is one of the most commercially important scombroid fish used as a food resource. Recently, there has been a demand for efficient rearing methods of this fish for a full‐life cycle aquaculture. In the present study, we evaluated the physiological responses in the juvenile S. japonicus to different ambient salinities. A significantly higher gain of the body mass was observed in the juveniles reared in 24 g/L and 13 g/L seawater than in those reared in natural seawater (34 g/L) within 40 days of the experimental period without affecting mortality. A principal enzyme for osmoregulation, Na⁺/K⁺‐ATPase, was expressed in the ionocytes located in the gill filaments of the juveniles. The number and the cell size of ionocytes and the enzymatic activity of Na⁺/K⁺‐ATPase in the gills decreased within 10 days after the low‐salinity challenge, which implies the reduction of the energy‐consuming active ion secretion under the low‐salinity environment. The physiological capacity for adaptation to low‐salinity seawater in chub mackerel could be basic knowledge to carry out culturing of these fish in coastal sea pens where ambient salinity fluctuates. The improvement of the growth performance by rearing in low‐salinity seawater will contribute to the efficient production of the seed juveniles for aquaculture.     

即食苍南鱼饼的研制

即食苍南鱼饼是以鲅鱼等海水鱼为原料,经取肉、斩拌、调味、成型、熟化、真空包装、高温杀菌等主要工艺制作而成。其原辅料主要为鲅鱼等海水鱼、水、淀粉、蛋清、白糖、盐、味精和磷酸盐等。     

乳酸菌发酵鲐鱼加工下脚料的初步研究

本试验研究乳酸菌发酵对鲐鱼加工下脚料的影响。试验主要测定了乳酸菌对鲐鱼加工下脚料中微生物的抑菌性能,分析了乳酸菌发酵产物营养成分和感官特性的变化。试验结果是,乳酸菌可以明显的抑制鲐鱼加工下脚料中微生物的生长;鲐鱼加工下脚料经乳酸发酵48h后,蛋白、脂肪、灰分和水分的含量没有显著变化,发酵产物感官性能较好。试验结果表明,利用乳酸菌发酵鲐鱼加工下脚料不会改变其的营养价值,而且还可改善下脚料的风味和延长贮藏期。